Return to BSD News archive
#! rnews 4009 bsd Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!feed1.news.erols.com!news From: Ken Bigelow <kbigelow@www.play-hookey.com> Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Two devices with same IP Date: Sat, 23 Nov 1996 09:47:57 +0000 Organization: Erol's Internet Services Lines: 73 Message-ID: <3296C84D.6B55@www.play-hookey.com> References: <56ltqk$nhv@csugrad.cs.vt.edu> <56lvvc$62f$1@gail.ripco.com> <56m19m$u08@csugrad.cs.vt.edu> <328EF58B.16E4@www.play-hookey.com> <56scbl$29d@anorak.utell.net> <32920988.63E7@www.play-hookey.com> <574f39$2rt@anorak.utell.net> Reply-To: kbigelow@www.play-hookey.com NNTP-Posting-Host: kenjb05.play-hookey.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0 (Win16; U) Brian Somers wrote: > > In article <32920988.63E7@www.play-hookey.com>, > Ken Bigelow <kbigelow@www.play-hookey.com> writes: > : Brian Somers wrote: > >> Of course this assumes that all but one of the interfaces have a netmask > >> of 0xffffffff :) > >> > : > : Sorry, brian, but no. From my /etc/sysconfig file: > : > : > : network_interfaces="cuaa1 lnc0 lo0" > : ifconfig_cuaa1="inet 206.161.179.129 netmask 255.255.255.224" > : ifconfig_lnc0="inet 206.161.179.129 netmask 255.255.255.224 mtu 1006" > : ifconfig_lo0="inet localhost" > : > : The only thing I have changed in months has been the mtu setting, and > : that was because of some messing around that my ISP did. These settings > : have always worked fine, as you can see by visiting my site (URL in my > : sig). In fact, I am at this moment answering via Netscape 3's newsreader > : in Win 3.1 (for a specific reason) on one of the computers in my subnet. > : Seems to still be working fine. > > First, I assume that you don't mean cuaa1 - there's no cuaa1 device in > my kernel anyway. If you *do* mean cuaa1, when /etc/netstart executes > > ifconfig cuaa1 inet 206.161.179.129 netmask 255.255.255.224 > > it'll do nothing but produce an error message. Not so. I *do* mean cuaa1; cuaa1 = com2 = my 33.6k modem. When pppd starts, the starting command in /etc/rc.local is: pppd /dev/cuaa1 115200 This interface *becomes* ppp0 when the connection gets established, but has to start as just cuaa1 during bootup, when I have no ppp connection. (It is possible that the spec of 206.161.179.129 in /etc/ppp/options automatically connotes a singleton IP address with ~~.255 netmask, but I didn't specify that.) > > Assuming cuaa1 is something else (ppp0, tun0), what happens when you send > a packet to 206.161.179.{225-254} ? Does it send it down the lnc0 > interface or the {insert whatever was meant by cuaa1} interface ? I don't > get what the above config lines are trying to say. My actual IP block is from ~~.128 through ~~.159 , so sending something to an address outside this range accomplishes nothing. The netmask, in hex, is ff.ff.ff.e0 which gives me a 32-node subnet. The mask only means that my subnet can use any combination of the last five bits (the zeros), not that it will respond to such an address. The ones in the mask only mean that the rest of my IP address is locked. Now, if I leave my "personal" PC (206.161.179.133, code-named frey) on and running FreeBSD while I'm at work, I can telnet/ftp to it from work without a problem. The gateway (code-named odin) gets the external packets through the ppp0/cuaa1 interface, passes them through to lnc0, and lets them go on to frey, which responds appropriately. No fuss, no muss. The same holds true for other machines on my home network (also named for Norse gods and places; don't ask why). If I leave them on and running FreeBSD, I can access them from inside or out, and I can access the outside world from any of them. They all simply specify 206.161.179.129 as their gateway. -- Ken Are you interested in | byte-sized education | http://www.play-hookey.com over the Internet? |